I wouldn't pick them all up, on the sides of the blanket. There is a difference in size between vertical stitches and horizontal ones. When you pick up the edge of a cardigan front, for example, you're supposed to pick up 3 out of 4 so the band isn't longer and sag. If you pick up every stitch of the blanket, it won't lie flat. Estimate how many rows you have and subtract 124 from that so you know how many stitches you need to skip.